Apparatus and exposure mask having cylindrical bending prevention member for forming a liquid crystal fence

ABSTRACT

In a backlight assembly, an assembled substrate on which a spacer including a light-curable material is formed is disposed on a base body and a light supply unit disposed on the base body provides a light to the assembled substrate so as to cure the spacer. An exposure mask formed with an opening is positioned at a path through which the light is supplied so as to selectively supply the light to the spacer of the assembled substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 10/454,487,filed Jun. 5, 2003, which claims priority to Korean Patent ApplicationNo. 2002-69468, filed Nov. 9, 2002, the disclosure of which in itsentirety is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for forming a liquidcrystal fence, and more particularly to an apparatus for forming aliquid crystal fence disposed between a TFT (Thin Film Transistor)substrate and a color filter substrate so as to provide a space forreceiving liquid crystal and to couple the TFT substrate to the colorfilter substrate.

2. Description of the Related Art

In an LCD (Liquid Crystal Display) panel, liquid crystal is interposedbetween a TFT substrate and a color filter substrate manufacturedthrough fabricating processes different from each other.

An alignment of the liquid crystal is changed corresponding to anelectric field formed between the TFT and color filter substrates inresponse to an external power voltage, so the liquid crystal changes atransmittance of a light provided from an external environment.

The TFT substrate and color filter substrate are separated from eachother with a predetermined distance (hereinafter, referred to as a cellgap) so as to provide a space for receiving the liquid crystaltherebetween. The cell gap between the TFT substrate and the colorfilter substrate depends on inherent properties of the liquid crystal.For example, if an LCD panel has a liquid crystal of a TN (TwistedNematic) mode, the cell gap is about 4.6 .quadrature.

In order to supply a liquid crystal to the cell gap between the TFT andcolor filter substrates, a method that supplies the liquid crystal in avacuum state (referred to as a vacuum method) or a method that suppliesthe liquid crystal in a lower-pressure state than an atmosphericpressure (referred to as a dropping method) are generally used.

In the vacuum method, the LCD panel having the cell gap is dipped into abarrel in which the liquid crystal is received. When an inside of thecell gap is changed into the vacuum state, the liquid crystal is suckedup from the barrel into the cell gap due to a pressure differencebetween the inside of the cell gap and the barrel in which the liquidcrystal is received. Thus, the inside of the cell gap may be filled upwith the liquid crystal without a void.

However, in the vacuum method, the liquid crystal may be supplied to theinside of the cell gap much greater than a required amount of the liquidcrystal. As a result, a pressing process is needed to drain the liquidcrystal supplied to the inside of the cell gap after the liquid crystalis supplied to the cell gap. Also, processes, for example, such as asealing process for sealing an inlet through which the liquid crystal issupplied and a cleaning process for cleaning the LCD panel stained withthe liquid crystal while the liquid crystal is supplied, are separatelyneeded.

In the dropping method, one of the TFT substrate and the color filtersubstrate is provided with a sealant that comprises anultraviolet-curable material so as to define a liquid crystal receivingarea. The liquid crystal is supplied to the liquid crystal receivingarea defined by the sealant. The TFT substrate is assembled with thecolor filter substrate in the lower-pressure state than the atmosphericpressure after the liquid crystal is supplied to the liquid crystalreceiving area. When the TFT substrate assembled with the color filtersubstrate is exposed to the atmospheric pressure, the liquid crystaldisposed between the TFT and color filter substrates is uniformlydiffused inside the liquid crystal receiving area due to the differencebetween the pressure of the liquid crystal receiving area of the LCDpanel and the atmospheric pressure. Then, the sealant is cured by anexposure to ultraviolet rays.

However, the ultraviolet rays for curing the sealant is irradiated ontothe TFT and color filter substrates and the liquid crystal with thesealant. As a result, an alignment layer of the TFT substrate may bedamaged and the liquid crystal may be deteriorated.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for forming a liquid crystalfence, which is capable of reducing damage of an LCD panel.

In one aspect of the invention, an apparatus for forming a liquidcrystal fence includes a base body, an assembled substrate, a lightsupply unit and an exposure mask.

The assembled substrate is mounted on the base body. The assembledsubstrate is divided into a liquid crystal receiving area and a liquidcrystal fence area surrounding the liquid crystal receiving area. Also,the assembled substrate includes two substrates and a spacer disposedbetween the two substrates, formed at the liquid crystal fence area andcured by an exposure to a light.

The light supply unit supplies the light to the assembled substrate.

The exposure mask is disposed on the assembled substrate so as to cut afirst light of the light supplied to the liquid crystal receiving areaand transmit a second light of the light supplied to the spacer, therebychanging the spacer into a liquid crystal fence.

According to the present invention, the light is selectively supplied tothe spacer that couples the two substrates to each other and the liquidcrystal is received in the liquid crystal receiving area, therebypreventing deterioration of the liquid crystal and an alignment layer orthe like.

Furthermore, the apparatus may prevent an increase in the temperature inand around both the assembled substrate and the light supply unit, dueto heat emitted from the light supply unit while the light is suppliedto the spacer.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of the present invention will becomereadily apparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic view showing an apparatus for forming a liquidcrystal fence according to an exemplary embodiment of the presentinvention;

FIG. 2 is a plan view showing an assembled substrate shown in FIG. 1;

FIG. 3 is a perspective view showing a light supply unit according to anexemplary embodiment of the present invention;

FIG. 4 is a schematic view showing an infrared rays filter for removingheat emitted from a light supply unit shown in FIG. 3 and awater-cooling type cooling unit;

FIG. 5 is a plan view showing an exposure mask according to an exemplaryembodiment of the present invention;

FIG. 6 is a schematic view showing a bending prevention member for anexposure mask according to an exemplary embodiment of the presentinvention;

FIG. 7 is a schematic view showing a bending prevention member for anexposure mask according to another exemplary embodiment of the presentinvention;

FIG. 8 is a schematic view showing a bending prevention member for anexposure mask according to another exemplary embodiment of the presentinvention;

FIG. 9 is a schematic view showing a bending prevention member for anexposure mask according to another exemplary embodiment of the presentinvention; and

FIG. 10 is a schematic view showing an apparatus for forming a liquidcrystal fence according to another exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic view showing an apparatus for forming a liquidcrystal fence according to an exemplary embodiment of the presentinvention. FIG. 2 is a plan view showing an assembled substrate shown inFIG. 1.

Referring to FIGS. 1 and 2, an apparatus 500 for forming a liquidcrystal fence includes a base body 100, a light supply unit 200 and anexposure mask 300.

The base body 100 is provided with an assembled substrate 400. Theassembled substrate 400 mounted on the base body 100 includes twosubstrates 410 and 420 and a spacer 450 disposed between the twosubstrates 410 and 420. The assembled substrate 400 is divided into atleast one liquid crystal receiving area 430 and a liquid crystal fencearea 440 surrounding the liquid crystal receiving area 430. The spacer450 is formed at the liquid crystal fence area 440 and comprises alight-curable material cured by an exposure to a light 201.

As shown in FIG. 1, the light supply unit 200 is disposed on the basebody 100 so as to supply the light 201 to the assembled substrate 400mounted on the base body 100. The light emitted from the light supplyunit 200 comprises ultraviolet rays.

FIG. 3 is a perspective view showing a light supply unit according to anexemplary embodiment of the present invention.

Referring to FIG. 3, the light supply unit 200 includes a housing 210, alamp 220 and a condensing cover 230.

The housing 210 has a rectangular box shape having an opening throughwhich the lamp 220 is inserted or ejected. The housing 210 includes acondensing cover 230 installed inside the housing 210.

The condensing cover 230 has a half-round shape and comprises a materialhaving a superior light reflectance. The condensing cover 230 isreceived into the housing 210 such that an inner surface of a protrudedportion is outwardly exposed.

The lamp 220 is received in the condensing cover 230 so as to besurrounded by the condensing cover 230. In this exemplary embodiment,the lamp 220 includes a mercury lamp that emits the ultraviolet rays 201having a peak wavelength of 365 nm (nanometers). This is because thespacer 450 shown in FIG. 1 is cured by an exposure to the ultravioletrays 201 having the peak wavelength of 365 nm. The ultraviolet rays 201radially emitted from the lamp 220 are condensed by means of thecondensing cover 230 and irradiated onto the assembled substrate 400shown in FIG. 1.

The light supply unit 200 supplies the ultraviolet rays 201 to theassembled substrate 400 while the light supply unit 200 is transferredby means of a transferring apparatus (not shown).

The lamp 220 emits an infrared rays, for example, such as a firstinfrared rays having a wavelength of 1014 nm, a second infrared rayshaving a wavelength of 1128 nm, a third infrared rays having awavelength of 1367 nm and a fourth infrared rays having a wavelengthsmaller than 1014 nm or greater than 1367 nm, with the ultraviolet rays201. The infrared rays include the first to fourth infrared rays of 45%,17%, 15% and 23%, respectively.

The infrared rays emitted from the lamp 220 with the ultraviolet rays201 are a heat rays, so that a temperature rise in and around the lamp220, for example, such as the assembled substrate 400 and the base body100 etc., may be caused. Particularly, in a case that the assembledsubstrate 400 is exposed to a temperature higher than an allowabletemperature for a long time, the heat emitted from the lamp 220 has tobe removed quickly since the assembled substrate 400 may be damaged dueto the beat.

FIG. 4 is a schematic view showing an infrared rays filter for removingheat emitted from a light supply unit shown in FIG. 3 and awater-cooling type cooling unit.

Referring to FIG. 4, an infrared rays filter 250 is installed at a path,for example, such as the opening of the condensing cover 230 throughwhich the ultraviolet rays 201 from the lamp 220 is emitted, and awater-cooling type cooling unit 260 is installed in association with theinfrared rays filter 250.

The infrared rays filter 250 may be manufactured in a manner that awater glass solution is coated over a plate glass or a dye that absorbsthe infrared rays is coated over the plate glass after melting a surfaceof the plate glass.

In order to cure the spacer 450, the infrared rays filter 250 transmitsthe ultraviolet rays 201 having the wavelength of 365 nm, and absorbs orreflects the infrared rays 202 having the wavelength from about 1000 nmto about 1400 nm to the condensing cover 230. Thus, an insidetemperature of the light supply unit 200 may increase but an externaltemperature of the light supply unit 200 may not increase.

The inside temperature of the light supply unit 200 increased due to theinfrared rays reflected from the infrared rays filter 250 to thecondensing cover 230 may decrease by using the water-cooled type coolingunit 260.

The water-cooled type cooling unit 260 has a pipe shape. Thewater-cooled type cooling unit 260 includes a circulation pipe 262through which a coolant 264 is circulated and a circulation unit (notshown) for circulating the coolant 264 inside the circulation pipe 262.The circulation pipe 262 is installed at an edge of the infrared raysfilter 250.

By cutting the infrared rays 202 emitted from the lamp 220 using theinfrared rays filter 250 and cooling the infrared rays filter 250 usingthe water-cooled type cooling unit 260, the temperature in and aroundthe lamp 220 may be maintained at about 60 Celsius degrees even when thelamp 200 having a high power of about 10 KW is always driven.

Referring to FIG. 1 again, the ultraviolet rays 201 emitted from thelight supply unit 200 are provided to the exposure mask 300 disposed onthe base body 100.

The exposure mask 300 cuts an ultraviolet rays 203 (hereinafter,referred to as a first light) supplied to the liquid crystal receivingarea 430 of the ultraviolet rays 201 emitted from the light supply unit200 and transmits a light 204 (hereinafter, referred to as a secondlight) supplied to the spacer 450. The spacer 450 is exposed to thesecond light 204 and changed into a liquid crystal fence having a highstrength.

FIG. 5 is a plan view showing an exposure mask according to an exemplaryembodiment of the present invention.

Referring to FIGS. 1 and 5, the exposure mask 300 includes a transparentsubstrate 310 and a light-cutting layer 330 formed on the transparentsubstrate 310 and partially opened so as to transmit the second light204 to the spacer 450. The light-cutting layer 330 is a chrome thinlayer that a chrome material is deposited on the transparent substrate310 using a sputtering method and the chrome thin layer is patterned bya photolithography to form the opened portion 320.

In this exemplary embodiment, the transparent substrate 310 comprisesglass or quartz and has a same size as that of the assembled substrate400. Also, the transparent substrate 310 may have a thickness of 0.7 mm,0.63 mm or 0.5 mm identical to a thickness of a TFT substrate and acolor filter substrate of the assembled substrate 400.

Recently, the exposure mask 300 has been gradually scaled up inaccordance with scaling-up of the assembled substrate 400. Although theassembled substrate 400 is scaled-up, the assembled substrate 400 maynot be bent because the assembled substrate 400 is mounted on the basebody 100. However, since the transparent substrate 310 of the exposuremask 300 is spaced apart from the base body 100, the transparentsubstrate 310 may be bent due to a dead load thereof.

If the transparent substrate 310 of the exposure mask 300 is bent, thelight-cutting layer 330 formed on the transparent substrate 310 isdeformed with the transparent substrate 310, so the second light 204 maynot be supplied to the spacer 450.

When the second light 204 is not supplied to the spacer 450 of theassembled substrate 400 or a part of the second light 204 is irradiatedonto the spacer 450, the spacer 450 may not be cured or may be partiallycured, thereby deteriorating the strength of the liquid crystal fence.As a result, a display quality of the LCD panel may be deterioratedbecause the cell gap between the TFT and color filter substrates is notuniform. Also, the TFT and color filter substrates may be separated fromeach other due to the cell gap not uniform and the liquid crystalinterposed between the TFT and color filter substrates may be leaked ata portion where the strength of the spacer 450 is deteriorated.

In order to prevent the transparent substrate 310 of the exposure mask300 from being bent due to the dead load thereof, the exposure mask 300further includes at least one bending prevention member 350.

Referring to FIG. 5, a plurality of supporters 350 is installed at thetransparent substrate 310 of the exposure mask 300 as the bendingprevention member 350. In this exemplary embodiment, since thesupporters 350 have structure and function identical to each other, oneof the supporters 350 will be described in detail and represented by areference numeral “350”. The supporter 350 is transparent and has aprism shape and a length suitable for supporting the transparentsubstrate 310. The supporter 350 is installed across the transparentsubstrate 310 of the exposure mask 300.

FIG. 6 is a schematic view showing a supporter for an exposure maskaccording to an exemplary embodiment of the present invention.

Referring to FIG. 6, a supporter 350 has a rectangular prism shape. Thesupporter 350 includes first, second, third and fourth side surfaces352, 354, 356 and 358 connected to each other. The first side surface352 makes contact with the transparent substrate 310 of the exposuremask 300 and the second side surface 354 faces the first side surface352 in parallel.

In case that the first and second side surfaces 352 and 354 are parallelto each other, the refraction of the ultraviolet rays 201 passingthrough the transparent substrate 310 and the supporter 350 may bereduced when the ultraviolet rays 201 are incident in a verticaldirection with respect to the transparent substrate 310 of the exposuremask 300.

FIG. 7 is a schematic view showing a supporter for an exposure maskaccording to another exemplary embodiment of the present invention. InFIG. 7, a supporter is represented by a reference numeral “360”.

Referring to FIG. 7, a supporter 360 is disposed on the light-cuttinglayer 330 formed on the transparent substrate 310 of the exposure mask300. In similar, the supporter 360 has same structure and function as inthose of the supporter 350 shown in FIG. 6. Also, in the supporter 360,a first side surface that makes contact with the light-cutting layer 330and a second side surface that faces the first side surface are parallelto each other so as to reduce the refraction of the ultraviolet rays 201provided from the light supply unit 200.

FIG. 8 is a schematic view showing schematic a supporter for an exposuremask according to another exemplary embodiment of the present invention.In FIG. 8, a supporter is represented by a reference numeral “370”.

Referring to FIG. 8, a supporter 370 has a cylindrical shape. Thesupporter 370 makes contact with a lower surface of the transparentsubstrate 310 of the exposure mask 300.

FIG. 9 is a schematic view showing a supporter for an exposure maskaccording to another exemplary embodiment of the present invention. InFIG. 9, a supporter is represented by a reference numeral “380”.

Referring to FIG. 9, a supporter 380 has a cylindrical shape. Thesupporter 370 makes contact with an upper surface of the light-cuttinglayer 330 formed on the transparent substrate 310 of the exposure mask300.

In order to reduce the refraction of the ultraviolet rays 201, thesupporters 370 and 380 having the cylindrical shape as shown in FIG. 8may be applied to a case that the ultraviolet rays 201 are irradiatedonto the assembled substrate 400 in an inclined direction with respectto the assembled substrate 400 as shown in FIG. 10.

FIG. 10 is a schematic view showing an apparatus for forming a liquidcrystal fence according to another exemplary embodiment of the presentinvention. In this exemplary embodiment, a detailed description of abase body 100 and an assembled substrate 400 having same structure andfunction as in those of the base body 100 and assembled substrate 400will be omitted.

Referring to FIG. 10, a light supply unit 200 irradiates ultravioletrays 205 onto an upper surface of the base body 100 in an inclineddirection with respect to an imaginary line perpendicular to an uppersurface of the base body 100. In order to irradiate the ultraviolet rays205 onto the spacer 450 in the inclined direction with respect to theimaginary line, an opening, through which the ultraviolet rays 205 areemitted, of a housing 210 of the light supply unit 200 may be adjustedso as to be inclined with respect to the imaginary line at apredetermined angle.

When the ultraviolet rays 205 emitted from the light supply unit 200 areirradiated onto the spacer 450 in the inclined direction with respect tothe imaginary line, the ultraviolet rays 205 may be easily irradiatedonto the spacer 450 regardless of parts of an assembled substrate 400,for example, such as a black matrix and gate and data lines and so on.

Accordingly, an efficiency of the ultraviolet rays 205 may be improvedwhen the ultraviolet rays 205 emitted from the light supply unit 200 areirradiated onto the spacer 450 in the inclined direction with respect tothe imaginary line than the ultraviolet rays 205 are irradiated onto thespacer 450 in a direction parallel to the imaginary line.

The ultraviolet rays 205 emitted from the light supply unit 200 aresupplied to the spacer 450 through an opening 320 formed at alight-cutting layer 330 of the exposure mask 400.

Although the exemplary embodiments of the present invention have beendescribed, it is understood that the present invention should not belimited to these exemplary embodiments but various changes andmodifications can be made by one ordinary skilled in the art within thespirit and scope of the present invention as hereinafter claimed.

1. An apparatus for manufacturing a liquid crystal display (LCD),comprising: a base body supporting a panel comprising two substrates anda plurality of spacers disposed between the two substrates, the panelbeing divided into a plurality of sections arranged in a matrix and eachsection being divided into a liquid crystal receiving area and a liquidcrystal fence area surrounding the liquid crystal receiving area, eachspacer being formed within the liquid crystal fence area; a light supplyunit supplying a light to the panel; and an exposure mask entirelycovering the panel and arranged between the panel and the light supplyunit, the exposure mask comprising a plurality of openings correspondingto the liquid crystal fence areas to expose the liquid crystal fenceareas to the light to change the spacers into liquid crystal fenceswhile preventing the liquid crystal receiving areas from being exposedto the light; and a bending prevention member supporting the exposuremask to prevent the exposure mask from being bent, wherein the bendingprevention member is transparent; the bending prevention member has arectangular prism shape when the light is irradiated in a directionperpendicular to the panel; and the bending prevention member isdisposed on one of a surface of the exposure mask facing the lightsupply unit and a surface of the exposure mask facing the panel.
 2. Theapparatus of claim 1, wherein the spacers comprise anultraviolet-curable material, and the light is ultraviolet rays.
 3. Theapparatus of claim 1, wherein the light supply unit comprises: a lampfor emitting ultraviolet rays; and a condensing cover condensing theultraviolet rays emitted from the lamp.
 4. The apparatus of claim 3,wherein the light supply unit further comprises a filter for cuttinginfrared rays emitted from the lamp.
 5. The apparatus of claim 4,wherein the filter is coated with a dye absorbing the infrared rays ofthe light.
 6. The apparatus of claim 4, wherein the light supply unitfurther comprises a cooling unit circulating a coolant.
 7. The apparatusof claim 6, wherein the cooling unit is a water-cooled type cooling unitdisposed at an edge of the filter, and the water-cooled type coolingunit includes a circulation pipe through which the coolant iscirculated.
 8. The apparatus of claim 1, wherein the light supply unitirradiates the light in a direction perpendicular to an upper surface ofthe panel.
 9. The apparatus of claim 1, wherein the light supply unitirradiates the light in a direction inclined with respect to an uppersurface of the panel.
 10. The apparatus of claim 1, wherein the exposuremask comprises: a transparent substrate; and a light-cutting layerformed on the transparent substrate and partially opened so as totransmit the light towards the spacers.
 11. The apparatus of claim 10,wherein the transparent substrate is formed of glass or quartz, and thelight-cutting layer is formed of chrome.
 12. The apparatus of claim 1,wherein the bending prevention member comprises a first surface makingcontact with the exposure mask and a second surface facing and parallelto the first surface.
 13. The apparatus of claim 12, wherein the lightis irradiated in a direction perpendicular to the panel and the firstand second surfaces of the bending prevention member.
 14. The apparatusof claim 1, wherein the bending prevention member is formed of quartz.